Piping systems are widely used throughout the construction industry for storm sewers, culverts, underground detention and/or retention, stormwater management, sanitary sewer and many other purposes related to drainage. These piping systems are typically complex and spread over a large area. As a result, the construction of such systems invariably results in the connection of pipe segments to one another. Where pipe segments are joined, they should be adequately connected to prevent leakage that can lead to erosion and costly repairs, as well as environmental damage.
The ability to join pipe segments during construction is often complicated by the need to cut pipes or fittings to size, meaning that the joining process occurs in the field, often with the pipe already situate in its end location in a trench, particularly in the case of field repairs. This can lead to even greater difficulty in achieving water tight joints at levels consistent with industry standards and/or required by environmental regulations.
While various methods have been used over the years for connecting different types of pipe segments in such systems, connecting corrugated pipe, sometimes referred to as profile-wall pipe, presents some additional challenges. One current method for joining corrugated pipe segments is the use of a wrap-around coupler that utilizes a mastic material to seal the joint between pipes. However, these types of couplers are expensive and may fall short of providing an in situ water-tight connection, particularly in instances of high groundwater levels. As a result, this coupler is not ordinarily considered a viable option in many situations.
Another option that better meets water tight standards for plain-end or field-cut corrugated pipe is a bell/bell coupler. However, one problem with this type of coupling system is that it requires gaskets to fill the valleys of the corrugated pipe, resulting in added expense. In-line bell and spigot configurations generally use spigots with reduced corrugations containing a groove at the crest to fit a low profile, economized gasket. As a result, plain-end or field-cut pipe uses a gasket to completely fill the valley between corrugations. The larger the pipe, the larger the space between corrugations, further increasing the expense of the valley gasket.
Heat fusion has been used to join smooth wall pipe segments, particularly where straight pipe is joined with fittings, in which fusible couplers in the form of collars or rings containing helically wound strands of embedded wire to facilitate electrofusion are used. Aside from being cost prohibitive for field joining, this solution is not useful for corrugated pipe due to its profile and differences in wall thickness.
What is currently lacking is a reliable, cost-efficient method for coupling thermoplastic corrugated pipe segments in the field in a robust, workable manner.
It would be desirable to provide a method of coupling corrugated pipe segments that meets some or all of these needs.